ELECTRICAL MACHINE WITH MULTI-DISC COMMUTATOR

MACHINE ELECTRIQUE A COLLECTEUR MULTIDISQUE

English Abstract

ABSTRACT:
The invention relates to an electrical
machine comprising a rotor provided with coils, which
rotor comprises a commutator having a commutator disk
whose surface is provided with segments, an end of each
being connected to a corresponding plurality of said
segments. The commutator comprises an assembly of
connecting elements which are insulated from one another,
the assembly being arranged adjacent the commutator disk in
the axial direction and the number of elements correspon-
ding to the number of coils. The coils ends are connected
to the connecting elements and each connecting element
is provided with lugs for the electrical connection of
the connecting element to a plurality of segments, which
lugs bridge the axial distance from the connecting
element to the segments.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PRO-
PERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An electrical machine comprising a rotor including
a plurality of coils, said rotor being provided with a com-
mutator having a commutator disk, said commutator disk hav-
ing a surface which is provided with segments, one end of
each of said coils being connected to a corresponding
plurality of said segments, said commutator including an
assembly of a plurality of connecting elements which are
axially separated by insulation from one another and from
said commutator disk, said assembly being disposed axially
adjacent said commutator disk, the number of said connecting
elements corresponding to the number of coils an end of
each coil being connected to a corresponding one of said
connecting elements and said commutator includes lugs for the
electrical connection of each of said connecting elements to
a plurality of said segments said lugs bridging an axial
separation between said segments and said connecting elements.
2. An electrical machine as claimed in Claim 1, char-
acterized in that each connecting element takes the form of
an annular part made of a sheet material and formed inte-
grally with said lugs which are regularly spaced around
the circumference of the connecting element.
3. An electrical machine as claimed in Claim 1 or 2,
characterized in that the one of the lugs of each connecting
element extends in radial direction and forms a connecting
strip for a coil end.

Description

PHN 10-459 1 8.8.1983
The :I.n~ention relates to an electrical
maohlne comprising a rotor with coils 9 ~rhich rotor
is pro~icled with a commutator havlng a commutator disk~
a surface o~ ~hich is provided with segments) one end of
each coil being connected to a corresponding plurality of
said s0gments.
Such an electrical machine is known, ~or
example from DE-OS 1,638,2L~7. Especially in small motors
in which the ratio between the number of segments and the
number of coils is large the connection o~ the coil ends
to the segments is a tedious, time-consuming and there-
~ore expensive manual operation.
The construction in accordance ~ith the
invention is simpler and cheaper to manu~acture and is
characterized in that the commutator comprises an assemb].y
o-~ connecting elements which are insulated from one another,
the assembly being arranged adjacent the commutator disk in
the axial direction and the number of elements correspon-
ding to the number o~ coils, an end of each coil being
connected to a corrasponding one of the conneoting elements
and the commutator being provided with lugs ~or the
electrical connection of each connecting element to a
corresponding plurality o~ said segments, which lugs
bridge the axial distances between the segments and the
connecting elements.
: Generally~ a coil end now has to be connected
only once to the commutator.
Moreo~er9 this construction is parti.cu~rl~
suitable ~or automated manufac-ture.
A preferred embodiment is c~aracterized in
that each connecting element takes the ~orm of an annular
part made o~ a sheet material and ~ormed integrally with
j~,3

~5~
PHN 100459 2 8.8.1983
said lugs, which are regularly spaced around the circumfe-
rence of the connecting element.
A special embodiment is characterizecl in that
one of the lugs of each connectillg element extencls ln a
radlal cl:Lrection and forms a connectlng strip :~`or a coil
encl.
~ n em'bodiment of the :Lnvention ~ill now be
clescri'bed in more detail~ by way of example~ with
reference to the Figures.
Figure I is a perspective view of a rotor of
an electric motor.
Figure 2 is a side view, partly in section
of the rotor shown in Figure 1.
Figure 3 is an ele~ation of the oommutator of
the rotor shown in Figure 2.
Figure 4 shows a stage in the manufacture o:E
connecting elements of the commutator s'hown ln the preee-
ding Figures~ the elements being shown still attached to a
strip of sheet material from which the~ are manufactured.
2n The rotor 'I shown in Figure 1 is a component
of an electric motor~ not shown~ and comprises a spindle
2 ~ith a disk-shaped armature 3 and a commutator 40 T'he
armc~re is provided with five coils 5 whose ends 6 are
connected to the segments 7 on the surfaee 3 of the
25 eommutator disk 9. During operation of the motor the ooils
5 are energized alternately in known manner by means of
brushes~ not sho~n~ whieh are positioned against the
surface 8 and whieh make contaet with the segments 7 in
sueeession.
3D In addition to the commutator disk 9 the i
commutator 4 (Figures 2 and 3) eomprises an assembly of
five eormeeting elements 10 insulated from one another by
f-our spaeers 110 The assembly is arranged adjaeent the
eommutator clisk 9 in the axial direction. The spaeers 11 ma~ -
35 be for example annular parts made of a plastics foil.
The conneeting elemerlts 10 are also suh-
stantially annular and are manufaetured from an eleotrieal-

5~
OPHN 10.459 3 8.8.1983
ly conductive sheet ma-terial~ for example a copper-alloy
sheet material. Each connecting element has three lugs 12
on its outer periphery~ which lugs are regularly spaeed
around the circum~erence of the connecting element. These
lugs l2 bridge the axial clistances betweell the eonnecting
elel~lerltslO ~ncl t'he segmellt~ 7 aTlCI ure eontleeted, ~or
e~a~llpLe 'by spol;-welcling7 to the outer encls 7~ of the
segmexlts~ ~hich ends project beyoncl the eclge of the eommu-
tator disk. ~aeh eonneeting element is thus eonneetecl via
its three lugs to a eorresponding three of the segments 7.
~ n -the embodiment shown in the Figures the
ends 6 of two eoils 5 may be eonnected to the radially
projecting end 12' of one lug 12, said coil ends thereby
being connected directly to three different segments 7 via
the relevant conneeting element~ Thus, by means o~ the
~ive conneeting elements 10 each of the ten eoil ends 6 can
be eonneeted to t'hree of the fifteen segments 77 for which
each eoil end has to be eonnected to the end 12' of only
one lug. This reduetion of the num'ber of soldered joints
20 substantially simplifies the manufaeture of the commutator
and moreover reduees the risk of mistal~es when selecting
the lug to which a eoil end has to he eonneeted.
The manufacture of a commutator as deseribed in
the foregoing can be au-tomated to a high degree~ The
connecting elements 10~ for example~ are fed in as shown
in Figure 4 as part of a strip 13 of the sheet material
from which they are manufactured. By means of a maehine
operation, the connecting elements are severed from the
strip aligned and formed into stacks with commutator disks
30 and spaeers~ The ends 12' of the lugs 12 are brought into
eontaet with the ends 7' of the commutator segments by a
simple bending operation and are eonneeted to the segments
by spot-welding. The radially projeeting ends 12' to which
no eoil end 8 is conneeted are cut of* where they project
35 beyond the outer ends of the segments.
It is obvious that the above construction of a
commutator may also be used if the arma-ture has a diffe-
:

5~
PHN 10~459 4 898.1983
rent shape from that sho~n and if the numbers ofsegments, coils and connecting elements are dif~erent
from the numbers of these parts in the smbodiment des-
cribed~
.